1. Field of the Invention
The present invention relates to a rack-and-pinion steering apparatus in which a steering gear box for transmitting an operation of a steering wheel to road wheels includes: a pinion operatively connected to the steering wheel; a rack bar which has a rack meshing with the pinion, and which is connected to the wheels; a housing for slidably supporting the rack bar; a cylindrical rack guide slidably fitted into a guide hole formed in the housing; and a spring member for causing the rack guide to abut on a rear of the rack bar by biasing the rack guide.
2. Description of the Related Art
A known rack-and-pinion steering apparatus is shown in Japanese Patent Application Laid-open No. 2005-247079.
FIG. 12 shows a conventional-type rack-and-pinion steering apparatus. A pinion 02 provided to a pinion shaft 01 meshes with a rack 04 provided on a rack bar 03. A cylindrical rack guide 07 slidably fitted into a guide hole 06 in a housing 05 is biased by a spring 08 in such a way as to abut on the rear of the rack bar 03, and thus restricts the deformation of the rack 04. This secures an appropriate meshing of the rack 04 with the pinion 02, and also prevents the rack bar 03 from bending due to a meshing reaction force.
A biasing force F1 from the spring 08 and a reaction force F2 from the rack bar 03 both act on the rack guide 07. Both a line of action of the biasing force Fl and a line of action of the reaction force F2 exist on the axis Lg of the rack guide 07. For this reason, looseness existing between the rack guide 07 and the guide hole 06 allows the rack guide 07 to vibrate. The vibration brings about a problem of causing noise.